1. Field of the Invention
The present invention relates to a recorded disk reproducing device.
2. Description of the Related Art
In a recorded disk for music information such as a CD or a MD or a recorded disk for computer information such as a CD-ROM or a HD, information is recorded on a spiral track formed on the surface of the disk. A recorded disk reproducing device for reproducing such a recorded disk radiates an optical beam such as laser beam to the track and receives reflected light modulated by the recorded information and converts the reflected light into an electric signal by means of an optical pickup and demodulates the electric signal to reproduce the information by means of a demodulating section. For this reason, the recorded disk reproducing device is provided with driving means such as a motor for moving the optical pickup in the radial direction of the recorded disk. For example, there is provided a mechanism in which the optical pickup joined to a threaded bar coupled to a motor shaft, is moved in the radial direction of the recorded disk by the rotation of the motor. An address is recorded on the track of the recorded disk for each predetermined unit of information, so that by designating the address of a target tack, the optical pickup can be moved from the present track to the target track.
The conventional recorded disk reproducing device is constituted in a manner described above, so that it has a problem that a mechanical load applied to the motor is varied from a designed value by variations in a mechanism for moving the optical pickup and a change in an ambient temperature to vary a moving time (also called a retrieval time) even when the optical pickup moves for the same number of tracks.